Trucks of Russian humanitarian convoy wait at the location outside Voronezh some 400 km outside Moscow on August 13, 2014. A massive Russian aid convoy rumbled towards Ukraine's border on August 13 as Kiev vowed to block what it feared could be a "Trojan horse" bringing military assistance to pro-Kremlin rebels fighting a bloody insurgency in the east. Russian television images showed a line of nearly 300 lorries moving through the countryside, covered with white tarpaulin and stretching over almost three kilometres (two miles). AFP PHOTO / VLADIMIR BARYSHEVVLADIMIR BARYSHEV/AFP/Getty Images

Confusion enveloped an enormous Russian aid convoy as it apparently halted Wednesday at a military base in the southern Russian city of Voronezh, temporarily suspending its march toward southeastern Ukraine.

At the very least, the two countries seemed headed toward a standoff, with Russia saying it still expected the hundreds of trucks to be allowed across the border and Ukraine vowing that they would be barred. As the crisis deepened, the European Union's foreign ministers scheduled an emergency meeting for Friday.

Amid the uncertainty, there was no clear statement from Russia about where the trucks were headed, and rumors began to fly that they would bypass the original point of entry, the Shebekino crossing, near Kharkiv, Ukraine, and head farther south to an area closer to Luhansk, where Russia and the separatist fighters it supports exert more control.

That would raise the possibility of the trucks entering the country against the express warnings of Kiev and without the contents being examined by the International Committee of the Red Cross, which Russia has pledged to have oversee the aid delivery.

The Russian government maintained that the convoy was still heading to Ukraine - although exactly where it would not say - and still working under the umbrella of the International Red cross, despite statements to the contrary from the organization.

"It is moving in the territory of the Russian Federation; it is still moving," Dmitri S. Peskov, the spokesman for President Vladimir Putin, told Russian reporters. "All this is going on in complete coordination with and under the aegis of the Red Cross."

The dispute over the convoy comes as Kiev is bearing down militarily on the separatist rebels - one of whose leaders, Igor Strelkov, was badly wounded Wednesday, Russian news media reported - forcing many of them to retreat into the region's two major cities, Donetsk and Luhansk, which they control.

Shelling there and elsewhere in the region by the Ukrainian forces has taken a heavy toll on civilians, with the death toll in the war doubling in the last week to more than 2,000, the United Nations' Office of the High Commissioner for Human Rights reported Wednesday.

Conditions in Luhansk, under siege by Ukrainian government forces, are particularly dire. City officials said Tuesday that its 250,000 residents had been living without power, water and a sewage system since Aug. 3, and that only essential food was available.